The present invention relates to an apparatus for feeding deck boards to the nailing head of a pallet making machine.
Machines for making pallets by nailing deck boards to stringers are well known in the art. Conventionally, pallets can be made in various sizes and with various numbers of stringers and deck boards. The stringers are parallel to one another and one spaced a predetermined amount and the deck boards are divided into a first and second series, each series being nailed to an opposite side of the stringers. Although the nailing of the deck boards to the stringers is essentially automated once begun, it has been common practice with many nailing machines to have an operator manually feed the deck boards, and in some instances the stringers, to the nailing head. The use of operators to feed boards to the nailing head, whether they be deck boards or stringer boards, is time consuming and slows production while adding to its cost. Manual board feeding also introduces the possibility of operator error in arranging the boards under the nailing head which may cause injury to the operator, a defective pallet, or damage to the pallet being nailed.
Attempts have been made to automate the feeding of boards to the nailing head, which include automatic stringer feeding conveyors. However, even with automatic stringer feeding, a manual operation is still usually required to place the deck boards on the stringers, with the attendant disadvantages noted above. Attempts at automatically feeding the deck boards as well as the stringers to the nailing head have not been generally successful because of the rough dimensions of the lumber typically used in manufacturing pallets which makes it difficult to design a reliable deck board feeder. In one known deck board feeding arrangement, described in U.S. Pat. No. 3,706,408, a single push bar is used to simultaneously transport all of the deck boards for a pallet from a hopper to the nailing head. However, this arrangement is not entirely reliable as it can jam when the deck boards are warped as the push bar tends to ride up and over curved or warped boards.